iambe. ] CANADIAN PALAEOZOIC CORALS. 163 



developed epitheca, with slight annular growth lines and strongly marked 

 septal furrows. Lateral connecting spurs short, distant, developed only 

 when the corallites by their flexions are brought almost into contact with 

 each other. Septa well developed, numbering from about forty to sixty, 

 carinated on their sides, alternately long and short, the longer not quite 

 reaching the centre of the visceral chamber, the shorter about half the 

 length of the primaries. Vesicles small, formed by regular curved 

 dissepiments in two rows, occupying the interseptal spaces near the wall. 

 Tabulae broad, flat or concave at the centre, deflected downward near the 

 margin, from about five to eight in a space of 5 mm. 



Localities andjormation. — Corniferous limestone of Ontario ; also a loose 

 specimen from Peace River, B.C., between Fossil Point and the Canon of 

 the Mountain of Rocks, collected by Professor John Macoun in 1875 

 (Devonian). 



Genus Acervularia, Schweigger. 1820. 



Acervularia, Schweigger. 1820. Handb. der Naturg., p. 418. 



"Corallum, composite, fasciculate or more often massive; increasing 

 by calicular gemmation. Corallites with two distinct walls as in Aulo- 

 phyllum. Septa well developed between the two walls but much less so 

 in the central area. No columella. Tabulae little developed." (Milne- 

 Edwards and Haime : Polypiers Fossiles). 



Type species. A. Boemeri, Milne Edwards and Haime. 



Mange. — Silurian and Devonian. 



This genus differs from Phillipsastrcea and Pachyphyllum principally 

 in having the limits of individual corallites defined by distinct walls, 

 whilst the inner mural investment distinguishes it from the composite 

 forms of Cyathophyllum. 



Acervularia gracilis, Billings. (Sp.) 



Plate XIV., figs. 2, 2a. 



Strombodes gracilis, Billings. 1865. Palaeoz. Foss. vol. I., p. 113, fig. 94. 

 Acervularia gracilis, Lambe. 1899. Ottawa Naturalist, vol. XII., p. 211. 



11 Original description. — { Corallum in large masses, consisting of cells 

 from 2 to 3 lines in diameter, most of them pentagonal. Cup about 1 

 line in depth, with an irregularly rounded central style J line in height, 

 and one-third or one half the whole width of the corallite. There appear 

 to be 30 or 40 septal striae on the inner side of the cup.' 

 L-5J 



